A Question of Balance

摘要

What's a genome to do when a molecular hiccup causes it to swell to twice its normal size? Somehow it has to get back to a reasonably sized, smoothly functioning genome, often by shedding genes. Once thought to be quite rare except in plants, whole-genome duplications-in which every chromosome winds up with an extra copy-are showing up in many animal lineages as well. These DNA windfalls pave the way for new proteins, traits, and species, depending on the patterns of gene loss and change that follow.